We’ve covered baptism already, and on occasion, an ordination does take place in a parish church:

§ 101 § Through the waters of baptism Christians are buried with Christ and rise to a new life with him. They are made sharers of God’s own life and members of Christ’s Body, the Church, and they are regenerated and cleansed of sin. In confirmation the seal of the Holy Spirit is set upon them, and their initiation is completed through their participation in the Eucharist. The specific spatial needs for the celebration of baptism and the Eucharist are addressed in the earlier sections of this chapter.

§ 102 § In the sacrament of holy orders, the ministry of word and sacrament is established and fulfilled. The sacrament is most often celebrated in the cathedral but may also be celebrated in the parish church. Planning should include space for the prostrations and the key liturgical actions such as the imposition of hands, the anointing, and the handing over of the vessels.